TRIAC are used for the control of power in AC circuits. A TRIAC is equivalent of two reverse parallel-connected SCRs with one common gate. Conduction can be achieved in either direction with an appropriate gate current. A TRIAC is thus a bi-directional gate controlled thyristor with three terminals. Figure 1 shows the schematic symbol of a TRIAC. The terms anode and cathode are not applicable to TRIAC. Figure 2 shows the V-I characteristics of the TRIAC.
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| Figure1: Schematic symbol of a TRIAC |
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| Figure2: Operating characteristics of TRIAC |